The invention relates to an aiming or targeting device for a locking nail or other implant for a long bone. More particularly, the invention relates to a device capable of holding drill guiding sleeves independently on the aiming device.
Locking nails insertable into the tibia or femur bone or other long bones are usually provided with several transverse bores. Bone screws are placed through the bores in order to keep the locking nails securely in the bone channel. A special problem with locking nails is the detection of the transverse bores in the implanted nail. Aiming devices are used for this purpose. One category of aiming devices works with X-rays, and the transverse bores of the locking nail in the bone are imaged on a monitor. Further, a representation of an aiming element aligned with the bores takes place. Thus, it is possible to mark the position on the outer side of the bone which is located on the axis of the transverse bore.
In another category, the aiming devices are fixedly attached to the implanted nail. A bracket-like portion is provided with at least one bore, the axis of which is aligned with the axis of a transverse bore of the nail while it is attached to the aiming device. For the purpose of guiding the drilling tool and the bone screw, respectively, it is also known to put a guiding sleeve through the transverse bore of the aiming device, which sleeve is moved forward until the outer side of the bone is reached.
The guiding sleeve is fittingly seated in the transverse bore of the first arm portion of the aiming device, but has to be moved easily by hand, in order not to complicate the work of the surgeon. Through this, there is the danger that the guiding sleeve slips rearwardly upon handling the aiming device, and upon drilling and also upon screwing in of bone screws, respectively. It has become known from U.S. Pat. No. 6,039,739, the teachings of which are incorporated herein by reference, to form a springy or resilient portion on the first arm portion of the aiming device which has the transverse bore or aiming bore of the aiming device, the resilient portion being provided with a bore which is aligned to the transverse bore. When the resilient portion is relaxed, the sleeve is held slightly clamped and is released when the resilient portion is deflected in the direction of the first arm portion.
For the operative repair of fractures in the femur head and neck region it is known to insert two longer bone screws approximately parallel, which are held by corresponding angled transverse bores of a locking nail. The first arm portion of the aiming device is provided with corresponding angled aiming bores. In order to maintain both guiding sleeves clamped, yet detachable, it is possible to provide the resilient portion of the known aiming device with two transverse passages. In this design, however, it is necessary that the two sleeves always must be clamped or released only at the same time.